After you consume a clone by transforming yourself from Travelbot to human, you get notification of the number of clones available, in the system chat message panel:
Translukator: You have 2 clones left. Always keep some in reserve. In order to reserve more clones, please see the officer at any outpost building.
When you become human and have only one clone left - this says:
Translukator: You have only one clone left! Always keep some in reserve, it is highly recommended to visit the officer at any outpost building to reserve more clones!
When you use the last clone to become human - this says:
Translukator: You have used your last clone. Please see the officer at any outpost building to reserve more clones!
If you then fail to purchase another clone - the next time you become Travelbot, an attempt to use the Translukator results in the following system chat:
Translukator: You don't have any clones available in reserve! Please ask someone to reserve a clone for you (tell to visit the officer at any outpost building and reserve a clone by giving your citizenship ID).
As that dialog states - you need to request another player to gift you a clone.
This costs the gifting player micro-P.Notes.
Until this has been done - you will be stuck in Travebot mode.
Once you have been gifted a clone - you will be able to become human again.